The Breast Cancer Task Force Treatment Program has supported a number of studies, many of which are still in progress, related to the treatment of breast cancer. In order to increase the usefulness of data produced in these various studies, a statistical support center is essential. Three major areas in which this facility will be utilized are: steroid receptor clinical correlation studies; biological tumor marker studies; and surgical adjuvant studies. The purpose of the proposed data center is to support analyses of collated data that are not possible at the individual institutions but not to duplicate the analysis performed in these institutions.